Split lib/ into nasmlib/ (for nasm-specific functions) and stdlib/
(for replacements for C library functions which may be missing.)
Rename the ersatz inttypes.h to nasmint.h so we can use a simple test
in compiler.h instead of dealing with include path magic.
Remove tests in configure.in for ancient missing functions (which will
break the build anyway.)
Signed-off-by: H. Peter Anvin <hpa@zytor.com>